SUMMARY OF SIGNIFICANT ACCOUNTING POLICIES - Revenue Recognition and Inventory (Details) - USD ($)	3 Months Ended		9 Months Ended
	Mar. 31, 2018	Mar. 31, 2017	Dec. 31, 2017
Disaggregation of Revenue [Line Items]
Revenue recognized	$ 90,296,000	$ 48,363,000
Contract with Customer, Asset and Liability [Abstract]
Deferred revenue balances, included in other short-term liabilities	200,000		$ 200,000
Deferred revenue balance	$ 56,000	0
Revenue, Practical Expedient [Abstract]
Company expects the collection cycle	true
amortization period	true
Medicare Parts B & C
Disaggregation of Revenue [Line Items]
Revenue recognized	$ 52,475,000	31,812,000
Commercial
Disaggregation of Revenue [Line Items]
Revenue recognized	34,834,000	15,136,000
Other
Disaggregation of Revenue [Line Items]
Revenue recognized	2,987,000	$ 1,415,000
Variable consideration
Disaggregation of Revenue [Line Items]
Revenue recognized	$ 8,500,000
One-time impact of certain payers
Disaggregation of Revenue [Line Items]
Revenue recognized			4,300,000
One-time impact of certain payers | Tests from previous year
Disaggregation of Revenue [Line Items]
Revenue recognized			$ 1,000,000